#pragma ident "$Id$"



/**
 * @file EllipsoidModel.hpp
 * Abstract base class modeling a Ellipsoid
 */

#ifndef GPSTK_ELLIPSOIDMODEL_HPP
#define GPSTK_ELLIPSOIDMODEL_HPP

//============================================================================
//
//  This file is part of GPSTk, the GPS Toolkit.
//
//  The GPSTk is free software; you can redistribute it and/or modify
//  it under the terms of the GNU Lesser General Public License as published
//  by the Free Software Foundation; either version 2.1 of the License, or
//  any later version.
//
//  The GPSTk is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU Lesser General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public
//  License along with GPSTk; if not, write to the Free Software Foundation,
//  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA
//
//  Copyright 2004, The University of Texas at Austin
//
//============================================================================

//============================================================================
//
//This software developed by Applied Research Laboratories at the University of
//Texas at Austin, under contract to an agency or agencies within the U.S.
//Department of Defense. The U.S. Government retains all rights to use,
//duplicate, distribute, disclose, or release this software.
//
//Pursuant to DoD Directive 523024
//
// DISTRIBUTION STATEMENT A: This software has been approved for public
//                           release, distribution is unlimited.
//
//=============================================================================



namespace gpstk
{
/** @addtogroup geodeticgroup */
//@{

/**
 * This abstract class encapsulates ellipsoid models (e.g. WGS84,
 * GPS, etc).
 */
class EllipsoidModel
{
public:
    /// @return semi-major axis of Earth in meters.
    virtual double a() const throw() = 0;

    /// @return semi-major axis of Earth in km.
    virtual double a_km() const throw() = 0;

    /// @return flattening (ellipsoid parameter).
    virtual double flattening() const throw() = 0;

    /// @return eccentricity (ellipsoid parameter).
    virtual double eccentricity() const throw() = 0;

    /// @return eccentricity squared (ellipsoid parameter).
    virtual double eccSquared() const throw()
    {
        return eccentricity() * eccentricity();
    }

    /// @return angular velocity of Earth in radians/sec.
    virtual double angVelocity() const throw() = 0;

    /// @return geocentric gravitational constant in m**3 / s**2
    virtual double gm() const throw() = 0;

    /// @return geocentric gravitational constant in m**3 / s**2
    virtual double gm_km() const throw() = 0;

    /// @return Speed of light in m/s.
    virtual double c() const throw() = 0;

    /// @return Speed of light in km/s
    virtual double c_km() const throw() = 0;

    /// Destructor.
    virtual ~EllipsoidModel() throw() {};

}; // class EllipsoidModel

//@}

} // namespace

#endif
